Newborn: 11 inch/28 centimeter (fits head circumference of 11.5-14 inch/30-36 centimeter)

0-3 months: 12.5 inch/32 centimeter (fits head circumference of 13-15.5 inch/34-40 centimeter)

3-6 months: 14 inch/36 centimeter (fits head circumference 14.5-17 inch/38-44 centimeter)

6-12 months: 15.5 inch/40 centimeter (fits head circumference 16.5-19 inch/42-48 centimeter).

Material: 97% Bamboo of Rayon, 3% Spandex